Online PHP editor | refs for mHv7L

<?php namespace Foo; define('Foo\\null', true, true); define('Foo\\false', true, true); define("Foo\\INF", 1337, true); echo 'null:';if (null) echo "TRUE";else echo "FALSE"; echo "\nfalse:";if (false) echo "TRUE";else echo "FALSE"; echo "\ntrue:";if (true) echo "TRUE";else echo "FALSE"; $n=acos(1.01); echo "\nNAN:".$n;